Earth working attachment tool and fastener structure therefor



1957 c. A. ROBINSON ETAL 3,305,955

EARTH WORKING ATTACHMENT TOOL AND FASTENER STRUCTURE THEREFOR 3 Sheets-Sheet 1.

Filed March 8, 1965 e w W MM P F. E 6. m VON m w V Mm H a m 28, 1967 c. A. ROBINSON ETAL 3,305,955

EARTH WORKING ATTACHMENT TOOL AND FASTENER STRUCTURE THEREFOR Filed March 8, 1965 3 Sheets-Sheet 2 FIG'4 INVENTOR5 Kim 4. Poem/saw 47- raeA/n 1967 c. A. ROBINSON ETAL 3,305,955

EARTH WORKING ATTACHMENT TOOL AND FASTENER STRUCTURE THEREFOR Filed March 8, 1965 3 Sheets-Sheet 5 INVENTOR5 CFC/4 A. Foam 501v BY 40m: )u/vaiaJ/ United States Patent 3,305,955 EARTH WORKING ATTACHMENT TOOL AND FASTENER STRUCTURE THEREFOR Cecil A. Robinson, RR. 3, Sullivan, Ill. 61951, and Lloyd Younger, Jr., RR. 2, Bethany, Ill. 61914 Filed Mar. 8, 1965, Ser. No. 437,914 12 Claims. (Cl. 37-145) This invention relates to an attachment tool for earth working blades and, more particularly, to a means for releasably securing the attachment tool to such blade.

As explained in the copending patent application of Cecil A. Robinson, Serial No. 226,417, filed September 26, 1962, now Patent No. 3,195,250, earth working blades are commonly employed on -self-propelled earth moving vehicles such as graders and tractors, and when used in conjunction with the latter are generally designated bulldozer blades. Such blades are supported on frame structure movably secured to the vehicle to enable the blade to be operator controlled and manipulated. For certain types of work, special attachment tools such as scarifiers or rooters are employed rather than the blade for earth working operations. In the main, such attachment tools either require substitution therefor of the earth working blade or necessitate manual handling and complex securing structures for mounting the attachment upon the blade.

The aforementioned copending patent application discloses an attachment tool and method of mounting the same upon the earth working blade of a tractor which tool and method not only eliminate the requirement for removing the blade from the vehicle but also eliminate the requirement for manual handling, lifting and other manipulation of the tool in mounting it on and removing it from such blade. The present invention constitutes a further advance in that it is concerned with an improved means for releasably securing such attachment tool to the earth working blade of a tractor or similar vehicle.

Accordingly, objects of the invention, among others, are to provide a structurally simple, inexpensive, versatile and effective means for detachably mounting an at tachment tool on an earth working blade or the like; and which means does not require weakening or other impairment of the blade as by providing connecting holes therein, which does readily accommodate the dimensional disparities inherent in earth working equipment of the type providing an environment for the invention, and which is of kinematic character in that it develops looking forces of great magnitude essential-1y independent of the masses of the earth working blade and attachment tool and significantly larger than the magnitude of the applied force requisite in the development of such locking forces. Additional objects and advantages of the invention will become apparent as the specification develops.

Embodiments of the invention are illustrated in the accompanying drawings in which:

FIGURE 1 is a broken perspective view of an attachment tool and mounting means therefor shown in association with an earth working blade carried by the movable frame structure of a tractor-type vehicle;

FIGURE 2 is an enlarged broken vertical sectional view taken generally along the line 2-2 of FIGURE 1;

FIGURE 3 is a transverse sectional view takenalong the line 33 of FIGURE 2;

FIGURE 4 is a vertical sectional view taken along the line 44 of FIGURE 2;

FIGURE 5 is a transverse sectional view taken along the line 55 of FIGURE 2;

FIGURE 6 is a broken vertical sectional view generally similar to that of FIGURE 2 but illustrating a modified construction;

. mounted thereon.

'ice

FIGURE 7 is a vertical sectional view taken along the line 77 of FIGURE 6; and

FIGURE 8 is a transverse sectional view taken along the line 88 of FIGURE 6.

Illustrated in FIGURE 1 is a conventional self-propelled vehicle in the form of a tractor 10 which has an earth working blade 11 mounted thereon in a conventional manner by means of a framework 12 adjustably supported by the tractor to permit an operator to raise, lower and angle the blade 11 by suitable and usual power operated mechanism indicated in part by a hydraulic motor means 13. The earth working blade 11 is in the form of a bulldozer blade and has a concave curvature along the front working face thereof which face is generally denoted with the numeral 14. The blade 11 also has along the lateral edges thereof end plates or forwardly projecting side wings 15, and along the bottom thereof a cutting edge 16 which may be detachably secured thereto.

Removably mounted upon the blade 11 is an attachment tool generally indicated with the numeral 17. The particular attachment tool shown is structurally simple, strong and rugged, and in the usual instance will be formed of steel. It comprises a unitary, ri'gid frame structure the components of which include a plurality of transversely spaced and upwardly extending (for convenience, the components will be described with respect to the upright orientation illustrated in FIGURE 1) scarifiers 18 especially shaped in the form of rooters and having downwardly projecting ground-engaging teeth 19. The scarifiers 18 are all rigidly interrelated as by means of a plurality of transversely extending braces 20 which are respectively interposed between adjacent scarifiers and are rigidly secured thereto as by welding. In the usual case, the braces 20 will be angle irons.

The teeth 19 project below the lowermost goo-up of braces 20 and the lower earth-penetrating ends of the teeth are desirably hardened, as by treatment thereof with case-hardening techniques. The scarifiers a-lso project above the uppermost set of braces 20, and at their upper ends are bolted or otherwise rigidly secured to a metal reinforcing plate 21. Along the rear face of the attachment tool, the scarifier have a convex curvature generally conforming to the concave curvature of the forward face of the blade 11, and the tool is in substantial abutment with such face of the blade when it is properly Such abutment with the blade reinforces the attachment tool and thereby provides a strong, rigid mounting therefor.

Means are provided for detachably mounting the tool 17 on the earth working blade 11, and such means include anchor structure provided by the attachment tool along the rear face thereof. More particularly, and referring to FIGURE 2, such anchor structure in the apparatus being considered comprises a plurality of hook members 22 respectively associated with at least certain of the scarifiers 18 and rigidly secured thereto as by means of welding. The hook members 22 are oriented in transverse alignment and each hook member is open at the top thereof, as indicated at 23, so as to define with the associated scarifier a slot for receiving the lower edge portion of the blade 11 thereinthat is, the bottom cutting edge 16 thereof.

As is evident in FIGURE 2, each of the hook members 22 is closed at its lower end and, therefore, defines a rigid abutment with the lower edge of the blade 11. As a consequence of such abutment, upward movement of the tool 17 with respect to the blade is positively limited; and such limiting constraint is usefully employed in mount-' ing the tool 17 upon the blade, as will be described in greater detail hereinafter.

The aforementioned means for detachably mounting the tool 17 on the earth working blade 11 also include a stress-developing fastener structure operative to apply between the tool and blade an axially or upwardly oriented force that tends to displace the tool upwardly with respect to the earth working blade. Such upward displacement is positively arrested by the rigid constraint defined by the hook members 22, and as a consequence thereof, the resultant stresses (the term stress being used herein to indicate total stress rather than unit stress, as is sometimes the case) developed within the tool and blade effectively integrate the same structurally into a functionally unitary earth working implement. In the particular tool and blade composition illustrated in FIGURE 1, four such fastener structures are employed and since they are all substantially identical, each is designated with the numeral 24.

More particularly, each such stress-developing fastener structure 24 includes a pair of buttress elements oriented in axially spaced opposition for the purpose of having an axially oriented force developed therebetween. The first buttress element, denoted 25 in FIGURE 2, is carried by the blade 11 and projects rearwardly from the rear face thereof. The element 25 may be in the form of a generally L-shaped. channel-one leg or flange of which is welded or otherwise rigidly secured to the blade, and the other being oriented in a generally horizontal disposition in the position thereof shown in FIGURE 2. Accordingly, such horizontal leg has an upwardly facing surface defining a purchase, the use of which will be described subsequently. The second buttress element is denoted with the numeral 26 and is carried by the attachment tool 17. above the buttress element 25.

Referring to FIGURES 3 and 4 in particular, it is seen that the upper buttress element 26 includes a pair of spaced apart flanges 27 and 28 which have a web 29 interposed therebetween that is welded to each. Forwardly of the web 29, the flanges 27 and 28 converge inwardly and are adapted to receive therebetween the associated scarifier 18. The buttress element is adjustably carried by the scarifier for selective axial positioning therealong, and to enable such adjustment, the scarifier is provided with a plurality of apertures or openings 30 therethrough which are axially spaced and are selectively alignable with a pair of axially spaced openings through the flanges 27 and 28 of the buttress element. With the openings appropriately oriented, bolts 31 and 32 may be inserted through the openings in the flanges 27 and 28 and through a pair of openings 30 in the scarifier 18 respectively aligned therewith, and the buttress element 26 thereby rigidly secured to the scarifier by tightening nuts onto the bolts 31 and 32. The web 29 has an opening 33 therethrough, and in the orientation of the components shown in FIGURE 2, the web is generally horizontally disposed and has a downwardly facing surface that overlies the up wardly facing purchase surface of the lower buttress element 25.

Each of the fastener structures also includes a strut member 34 interposed between the buttress elements 25 and 26 and arranged in force-applying engagement therewith. In the form shown, the strut member 34 comprises a pair of side plates 35 and 36, the first of Which has an arcuate upper end portion turned toward the plate 36 and rigidly related thereto by welding. At their lower ends, the plates 35 and 36 are each welded to a bearing element 37 in the form of a rod or pin having an arcuate undersurface. The bearing element 37 is adapted to seat upon and bear against the upper purchase surface of the lower buttress element 25.

The plate 36 at its upper end is formed integrally or is otherwise provided with an extension 38 dimensioned to pass through the opening 33 in the web 29 of the upper buttress element 26. Additionally, the extension 38 is threaded and has mounted thereon a nut 39, the upper surface 40 of which is a bearing element and is rounded so as to have a generally hemispherical configuration.

The undersurface of the web 29 is similarly rounded but in a complementary manner so as to seat the rounded upper surface 40 of the nut therein. Thus, the nut and web establish a ball and socket type joint effective to apply axial forces developed along the strut member 34 to the web 29 in a direction substantially normal to the plane thereof.

The fastener structure additionally includes a means for developing within the strut member 34 an axially oriented force tending to displace the attachment tool 17 in an upward direction relative to the earth working blade 11. In the structural embodiment of the invention being considered, such means is in the form of clamp structure and includes a tension strap 41 having at its forward end a hook 42 that extends about the associated scarifier 18 and provides a slot or channel 43 slideably receiving the scarifier therein. The strap 41 also includes a shank 44 equipped with threads therealong, and such shank extends between the side plates 35 and 36 of the strut member 34 and through an opening provided therefor in :a narrow plate or web 45 extending across and secured to the plates 35 and 36 along the rear edges thereof.

A hearing nut 46 is threadedly received on the shank 44 and is intended to be tightened against the rear surface of the plate 45, as shown best in FIGURE 5. The forward face of the nut 46 may be rounded so as to seat within the complementary configurated surface of the plate 45 about the aforementioned opening therethrough. Additionally, a lock-nut 47 may be tightened against the nut 46 to secure the same in the position of tightened adjust ment thereof. The scarifier 18 along the forward edge 48 of the upper end portion thereof is provided with a plurality of axially spaced notches or recesses 49 which selectively seat the hook-equipped end portion 42 of the tension strap 41 therein.

In use of the stress-developing fastener structure, the attachment tool 17 will have the general position thereof shown in FIGURES 1 and 2 relative to the earth working blade 11. As explained in the aforementioned patent application, such relative positioning of the attachment tool 17 and blade 11 is accomplished by first disposing the convex face of the tool at rest along the ground surface, whereupon the upper end portion of the tool will be spaced above the ground because of the curvature of the tool. The space thus provided between the ground and such upper end portion of the tool is adapted to receive the lower end portion of the earth working blade 11 therein as the vehicle 10 is propelled forwardly toward the tool.

Accordingly, and after such initial insertion of the blade, continued forward propulsion of the vehicle and blade elevates the top of the tool while its bottom end portion (i.e., the teeth 19) remains supported on the ground. Further continuance of such forward motion causes the lower edge portion 16 of the blade to be inserted into the slots 23 of the hook members 22, whereupon the convex rear face of the tool is brought into substantial abutment with the concave forward face 14 of the blade, as illustrated most clearly in FIGURE 2. In this position, the blade 11 and attachment tool 17 are susceptible of having each of the stress-developing fastener structures 24 connected therewith.

In such general position of the attachment tool 17 relative to the blade 11, and considering the assembly therewith of one of the fastener structures 24, the upper end portion 38 of the strut member 34 thereof is inserted through the opening 33 in the web 29 of the upper buttress element-it being assumed that the upper buttress element has been appropriately secured to the scarifier 18. The nut 39 is adjusted as necessary along the upper end 38 of the strut until the bearing element 37 thereof engages the upper purchase surface of the lower buttress element 25. Accordingly, the strut member 34 will then extend between the buttress elements and will substantially abut each. At this time, the strut member will be inclined somewhat and will extend upwardly and toward the right, as viewed in FIGURE 2, from the point of support of the bearing element 27 upon the lower buttress element 25. In this connection, it may be noted that the bearing element 37 is off-set rearwardly or to the left from the centerline of the strut 34 so as to functionally augment or amplify the incline of the strut.

Next, the strap 41 is positioned as shown in FIGURES 2 and 5 with the hook 42 engaging the scarifier 18 and nesting within a recess 49 thereof. At this time, the shank 44 of the strap is extended through the opening provided therefor in the plate 45 and the bearing nut 46 is then snugged up against the plate to maintain the strap in the illustrated position. Thereafter, the nut 46 is tightened which causes the strut 34 to be displaced toward the right at the lower end thereof or, more specifically, to be angularly displaced in a counter-clockwise direction, as seen in FIGURE 2, about an axis generally defined by the engaged complementary surfaces of the web 29 and nut 30. Such described displacement of the strut member assumes an initial condition of substantial abutment between the attachment tool 17 and earth working blade 11, whereupon the tool cannot be further displaced toward the left, as viewed in FIGURE 2, relative to the blade 11. However, should the attachment tool 17 not be in such condition of abutment with the blade 11, tightening of the nut 46 will draw the attachment tool 17 toward the left along the upper end portion thereof (that is to say, the attachment tool will be pivoted in a counter-clockwise direction about an axis defined by the abutment of the lower edge portion of the blade and hook members 22) until such condition of abutment is established. Thereafter, the strut 34 will be displaced toward the right as described.

The angular inclination of the strut member 34 is sufficient to space the lower end portion thereof a substantial distance from the rear face of the blade 11, and the forward edges of the side plates 35 and 36 of the strut may be rounded slightly, as shown at 50, to further increase such spacing. Therefore, tightening of the nut 46 affects a type of wedging action in which the strut is rogressively and incrementally wedged between the buttress elements 25 and 26 as the force applied by the strap 41 attempts to urge the strut out of the inclined disposition thereof and into a position of normalcy with respect to the lbuttress elements.

This wedging action develops within the strut an axial compressive force reactively applied to the buttress elements and tending to displace the upper buttress element 26, and therefore the attachment tool to which it is fixedly secured, upwardly relative to the earth working blade 11. However, since upward movement of the attachment tool is rigidly constrained by the anchorage defined by the interconnection of the hook members 22 with the lower edge of the blade, the consequent force development between the attachment tool and blade effectively integrates the same into a unitary earth working implement.

It may be noted that the tension strap 41 is disposed below the axial center of the strut 34 so as to maximize the force development upon the strut that tends to displace the same in the counter-clockwise direction as heretofore described, whereupon the consequent wedging action of the strut results in the development therealong of compressive stress significantly in excess of the value of the tensile force applied along the strap 41. After the bearing nut 46 has been sufficiently tightened, the lock-nut 47 can be turned thereagainst to secure the fastener structure in the adjusted position thereof. It will be evident that each of the fastener structures 24 will be tightened in the same manner which, in the specific structure illustrated, necessitates the positioning and securance of four individual fastener structures.

Conveniently, each of the upper buttress elements 26 will remain on the attachment tool as a semi-permanent component thereof after once being properly located thereon. However, should the attachment tool be used with different earth working blades, it might be necessary to reposition such upper buttress elements so that an adequate and proper spacing is initially established with the lower buttress element 25 of any particular blade. Thus, the adjustability of each upper buttress element 26 provides a type of coarse or approximate adjustment while the location of the nut 39 along each strut member may be used as a fine adjustment to initially establish abutment of the strut at the opposite ends thereof with the buttress elements.

The modified stress-developing fastener structure illustrated in FIGURES 6 through 8 is quite similar to the embodiment heretofore described in detail; and, accordingly, the primed form of the same numerals will be used where appropriate to designate respectively corresponding components.

As in the case of the prior embodiment, the attachment tool 17' is equipped with a plurality of transversely spaced scarifiers 18the forward edge 48' of which has a slight inward curvature or rearwardly converging inclination 49 that is used to help orient the tension strap instead of the receses 4? in the prior embodiment. The upper buttress element 26' is fixedly secured to the scarifier, as by means of welding and, therefore, is not susceptible to selective positioning along the length of the scarifier.

The buttress element 26 is provided with flanges 27' and 28 and a web 29 having an opening therethrough which receives the threaded upper end portion 38 of the strut 34'. The strut has a bearing nut 39' mounted thereon which cooperates with the flange 29' in the manner heretofore described. The spaced side walls 35' and 36' of the strut have a plate 45 extending therebetween and the threaded shank 44 of the tension strap 41 passes through an opening provided therefor in the plate. The tension strap 41' is equipped with a bearing nut 46, a lock-nut 47 and a hook 42', all of which serve the function heretofore described in connection with the tension strap 41.

The strut 34 is provided adjacent the lower end thereof with a bearing element generally denoted 37' which, in the structure illustrated, takes the form of a generally V-shaped notch or recess formed in each of the side plates 35' and 36'. The bearing recesses are oriented in transverse alignment and are adapted to seat therein the lower buttress element 25' which is welded or otherwise fixedly secured to the earth working blade 11 along the rear face thereof. As in the prior embodiment, the lower buttress element 25' is a generally L-shaped channel and the two flanges or legs thereof are of substantially the same width, and the respective longitudinal edges thereof are disposed in contiguous relation with the rear face of the blade and are welded thereto. Thus, the corner of the channel-shaped buttress element is spaced from the rear face of the blade, and the upper flange of the buttress element is inclined upwardly and forwardly from such corner.

The modified fastener structure performs the same function as the fastener structure heretofore described and, accordingly, with the attachment tool 17 being in substantial abutment with the earth working blade 11' (see FIGURE 6) and with the strut 34' being in engagement with the buttress elements 25' and 26, the strut initially has an angular disposition in which it is inclined downwardly and rearwardly or toward the left, as viewed in FIGURE 6. In such initial position, the comer of the buttress element 25' may be located along the upper inclined edge of the bearing recess 37 at a position much closer to the upper terminus thereof than the position shown in FIGURE 6. However, as the bearing nut 46 is tightened, the lower end portion of the strut 34' is displaced toward the right or, more specifically, the strut is angularly displaced in a counter-clockwise direction, as viewed in FIGURE 6, about an axis generally defined 7 by the engaged complementary surfaces of the web 29' and nut 39'.

Displacement of the strut in such manner causes it to ride upwardly along the corner of the buttress element 25' and into the position shown in FIGURE 6. As a consequence, a wedging action occurs, as described hereinbefore, with the result that an axial compressive force develops within the strut and is reactively applied to the buttress elements and thereby tends to displace the buttress element 26 upwardly. Therefore, the attachment tool 17', which is fixedly secured to the buttress element 26', tends to be displaced; but since upawrd movement of the attachment tool is rigidly constrained by the anchorage thereof to the earth working blade, the consequent stresses developed in the tool and blade effectively integrate the same into a unitary earth working implement.

While in the foregoing specification embodiments of the invention have been described in considerable detail for purposes of making a complete disclosure thereof, it will be apparent to those skilled in the art that numerous changes can be made in such details without departing from the spirit and principles of the invention.

What is claimed is:

1. The combination with an earth working blade of an attachment tool, anchor structure interconnecting said blade and tool and limiting relative displacement therebetween in one direction, a first buttress element on said blade, a second buttress element on said tool and being disposed in spaced relation with said first buttress element, a strut operatively disposed in force-applying enga-gement with said buttress elements, and a tension member connected between said strut and tool and maintaining said strut under stress which is respectively applied to said buttress elements to effectively integrate said blade and tool by tensioning one and compressing the other.

2. The combination with an earth working blade of an attachment tool equipped with an anchor structure engaging the lower edge portion of said blade and thereby limiting upward displacement of said tool with respect thereto, a first buttress element on said blade, a second buttress element on said tool and being spaced upwardly with respect to said first buttress element, a strut interposed between said buttress elements, and a tension member connected between said strut and tool and maintaining said strut under stress between said buttress elements and thereby maintaining said anchor structure in engagement with the lower edge of said blade, whereby said blade and tool are effectivelyv integrated by application of a tensile force to one and compressional force to the other.

3. In combination with an earth working blade: an attachment tool; and means detachably mounting said attachment tool on said blade comprising anchor structure interconnecting said blade and said tool and limiting relative displacement therebetween in one direction, and stress-developing fastener structure including buttress elements respectively provided by said blade and tool in spaced-apart relation for having an axial force developed in application thereto tending to displace said attachment tool relative to said blade in such one direction, said stressdeveloping fastener structure also including strut structure in force-applying engagement with said buttress elements, and further including means for developing within said strut structure in application to said buttress elements an axal force'tending to displace said attachment tool in such one direction limited by said anchor structure with the result that the consequent stress developed within said strut structure in its reactive application to said blade and attachment tool tensions one and compresses the other and thereby effectively integrates the same into a unitary work implement.

4. In combination with an earth working blade: an attachment tool; and means detachably mounting said attachment tool on said blade comprising anchor structure interconnecting said blade and said tool and limiting relative displacement therebetween in one direction, and stressdeveloping fastener structure including buttress elements respectively provided by said blade and tool in spacedapart relation for having an axial force developed in application thereto tending to displace said attachment tool relative to said blade in such one direction, said stress-developing fastener structure also including strut structure in force-applying engagement with said buttress elements, and further including a force-applying member connected with said strut structure and means for producing within said force-applying member a force applied thereby to said strut structure which develops therewithin in application to said buttress elements an axial force tending to displace said attachment tool in such one direction limited by said anchor structure with the result that the consequent stress developed within said strut structure in its reactive application to said blade and attachment tool tension one and compresses the other and thereby effectively integrates the same into a unitary work implement.

5. In combination with an earth working blade: an attachment tool; and means detachably mounting said attachment tool on said blade comprising anchor structure interconnecting said blade and said tool and limiting upward displacement of said tool with respect thereto, and stress-developing fastener structure including buttress elements respectively provided by said blade and tool in spaced-apart relation for having an axial force developed therebetween tending to displace said attachment tool upwardly relative to said blade, said stress-developing fastener structure also including strut structure interposed between said buttress elements'in force-applying engagement therewith, and further including means for developing within said strut structure in application to said buttress elements an axial force tending to displace said attachment tool in the upward direction thereof rigidly limited by said anchor structure with the result that the consequent compressive stress developed within said strut structure in its reactive application to said blade and attachment tool effectively integrates the same into a unitary work implement by compressing said blade and tensioning said attachment tool.

6. In combination with an earth working blade: an attachment tool; means detachably mounting said attachment tool on said blade comprising anchor structure interconnecting the lower edge of said blade and said tool and limiting relative displacement therebetween in one direction, and stress-developing fastener structure including buttress elements respectively provided by said blade and tool in spaced-apart relation for having an axial force developed therebetween tending to displace said attachrnent tool relative to said blade in such one direction, said stress-developing fastener structure also including strut structure interposed between said buttress elements in force-applying engagement therewith, and further including a force-applying tension member connected with said strut structure for developing therewithin and between said buttress elements an axial force tending to displace said attachment tool in such one direction limited by said anchor structure with the result that the consequent compressive stress developed within said strut structure in its reactive application to said blade and attachment tool tensions one and compresses the other and thereby effectively integrates the same into a unitary work implement.

7. The combination of claim 6 in which said strut structure is greater in length than the shortest axial distance between said buttress elements, and in which said tension member applies to said strut structure a force tending to wedge the same into such shortest axial distance, wherefore the compressive stress developed within said strut structure is a result of the wedging action defined between said buttress elements and strut structure.

8. The combination of claim 7 in which said tension element is connected with said attachment tool as well as with said strut structure, and in which means are included 9 for tensioning said tension element to apply the aforesaid force thereby to said strut structure.

9. The combination of claim 7 in which adjustment means are provided for selectively varying the axial length of said strut structure.

10. In combination with an earth working blade having a concave curvature along the front face thereof; an attachment tool comprising a rigid frame structure having a convex curvature along the rear face thereof generally conforming to the curvature of said blade and being disposed in substantial abutment with the concave front face thereof; and means detachably mounting said attachment tool on said blade comprising anchor structure interconnecting the lower edge portion of said blade and said tool and limiting upward displacement of said tool with respect thereto, and stress-developing fastener structure including buttress elements respectively provided by said blade and frame structure in spaced-apart relation for having an axial force developed therebetween tending to displace said attachment tool upwardly relative to said blade, said stress-developing fastener structure also including strut structure interposed between said buttress elements in force-applying engagement therewith and having a length greater than the shortest axial distance therebetween, and further including a force-applying tension member connected with both said strut structure and attachment tool and means for producing within said tension member a force tending to wedge said strut structure into such shortest axial distance to develop therewithin a compressive stress reactively applied against said buttress elements and thereby tending to displace said attachment tool in the upward direction thereof limited by said anchor structure, wherefore said blade is compressed and attachment tool tensioned by such reactive application of stress to said buttress elements with the result that said blade and attachment tool are effectively integrated into a unitary work implement.

11. An attachment tool and detachable mounting for use with an earth working blade, comprising a rigid frame structure provided by said attachment tool and being adapted to be disposed along the front face of such earth working blade in substantial abutment therewith, anchor structure carried by said frame for engagement with the lower edge portion of such blade to interconnect said attachment tool therewith and thereby limit relative displacement therebetween in one direction, strut structure for interconnection with said attachment tool and earth working blade in force-applying engagement with each to develop against said attachment tool an axial force tending to displace the same relative to the blade in such one direction and thereby maintain said anchor structure in engagement with the lower edge portion of the blade, a

force-applying tension member for connection between said strut and attachment tool for maintaining said strut under stress to thereby develop therewithin such axial force, and an adjustable means for creating along said tension member a tensile force applied thereby to said strut to so stress the same and thereby effectively integrate said attachment tool and such blade by tensioning one and compressing the other.

12. A stress-developing fastener structure for rigidly mounting an attachment tool such as a scarifier or the like to an earth working blade having a lower edge portion which is adapted to be engaged by anchoring structure carried by the attachment tool to interconnect the same with the blade and thereby limit upward displacement of the tool with respect thereto, comprising a longitudinally extending strut structure equipped with hearing elements adjacent the opposite ends thereof for respective engagement with a pair of buttress elements respectively provided by such attachment tool and blade so as to develop therebetween an axial force tending to displace the attachment tool relative to the blade in one direction and thereby maintain such anchoring structure in engagement with the lower edge portion of the blade, a force-applying tension member for connection with said strut structure and such attachment tool to place said strut structure in a condition of stress by means of which it develops the aforementioned axial force tending to displace the attachment tool in such one direction, said tension member including a hook portion for securance to the attachment tool and a shank portion, and an adjustable bearing member engageable with said shank portion and strut structure for developing a tensile force along said tension member which is applied thereby to said strut structure to stress the same and thereby develop such axial force to eifectively integrate such attachment tool and blade by tensioning one and compressing the other.

References Cited by the Examiner UNITED STATES PATENTS 2,718,075 9/1955 MacLeod et al. 37l45 2,783,559 3/1957 Forte 37145 2,797,505 7/1957 Rogers 37-145 2,837,844 6/1958 Launder 37145 2,860,426 11/1958 Allin et al 37--2 2,952,929 9/1960 Lindberg 37-145 3,195,250 7/1965 Robinson 37-145 ABRAHAM G. STONE, Primary Examiner.

JOE O. BOLT, JR., W. A. SMITH III,

Assistant Examiners. 

2. THE COMBINATION WITH AN EARTH WORKING BLADE OF AN ATTACHMENT TOOL EQUIPPED WITH AN ANCHOR STRUCTURE ENGAGING THE LOWER EDGE PORTION OF SAID BLADE AND THEREBY LIMITING UPWARD DISPLACEMENT OF SAID TOOL WITH RESPECT THERETO, A FIRST BUTTRESS ELEMENT ON SAID BLADE, A SECOND BUTTRESS ELEMENT ON SAID TOOL AND BEING SPACED UPWARDLY WITH RESPECT TO SAID FIRST BUTTRESS ELEMENT, A STRUT INTERPOSED BETWEEN SAID BUTTRESS ELEMENTS, AND A TENSION MEMBER CONNECTED BETWEEN SAID STRUT AND TOOL AND MAINTAINING SAID STRUT UNDER STRESS BETWEEN SAID BUTTRESS ELEMENTS AND THEREBY MAINTAINING SAID ANCHOR STRUCTURE IN ENGAGEMENT WITH THE LOWER EDGE OF SAID BLADE, WHEREBY SAID BLADE AND TOOL ARE EFFECTIVELY INTEGRATED BY APPLICATION OF A TENSILE FORCE TO ONE AND COMPRESSIONAL FORCE TO THE OTHER. 